Here
we have a handful of horsehair worms found In early February in a small
puddle on Outside Creek under the weir. They do appear like living and
skirming pieces of course hair or wire. As you can see their colors are
from light tan to dark brown with all different sizes.

Horsehair eggs are laid in the water in long strings where
the adults live. After hatching, the larvae penetrate some aquatic
insect; they escape in some unknown way from this host and find their way
into a second host; usually a beetle, cricket, or grasshopper; in the body
cavity of the second host the larvae continue their development eventually
passing out into the water where they become mature. Since the adults
live only in water, those that survive probably emerge from terrestrial
(flying) insects, which constitute their second hosts, that chance to
drown in watering troughs and small ponds.

(Many thanks to Richard Webb, member of Four Creeks Chapter,
for this information on harsehair worms. He credits INVERTEBRATE ZOOLOGY
by Robert W. Hegner, printed April, 1933.)